The present invention relates to the medical imaging arts. It particularly relates to the imaging and interpretation vascular structures imaged in three-dimensional medical images, such as multi-slice or spiral computed tomography (CT) images, and will be described with particular reference thereto. However, the invention will also find application in conjunction with other imaging techniques such as magnetic resonance-based imaging (MRI) or nuclear medicine, as well as in interpretation of other tortuous and/or furcating tubular structures having constant or variable diameters.
Based upon current and future trends in CT technology, cardiac imaging, and in particular coronary artery imaging, is an increasingly important application in which CT is expected to play a significant role. Coronary arteries supply blood feeding the heart muscle. Failure of a coronary artery can produces myocardial infarction leading to chronic heart problems and/or catastrophic heart attacks, which are a leading cause of death in the United States today.
On the data acquisition side, development of multi-slice CT systems having increasingly improved resolution particularly in the slice-direction are making clinical CT imaging of vascular systems attractive. However, for CT to gain greater clinical acceptance in this area, reconstruction and post-processing of the images at selected phase(s) of the cardiac cycle should be automated to the greatest extent possible. Currently, coronary artery tracking in multi-slice CT data is a cumbersome and laborious task. Prior art vessel tracking systems are typically not directed toward CT data, which has peculiar issues such as high noise levels when compared with techniques such as magnetic resonance imaging (MRI). Past vessel tracking systems which are directed toward multi-slice CT are limited by long computation times.
The present invention contemplates an improved vessel tracking method and apparatus which overcomes the aforementioned limitations and others.
According to one aspect of the invention, a method for tracking a blood vessel in a three-dimensional image is disclosed. An estimated vessel center is identified corresponding to a starting point lying within a vessel to be tracked. A vessel direction is estimated in the vicinity of the starting point. A planar image is extracted containing the estimated vessel center from the three-dimensional image, which planar image is perpendicular to the estimated vessel direction. The planar image is edge-enhanced. A corrected vessel center is located in the planar image. Vessel boundaries are found in the planar image. A new estimated vessel center is extrapolated along the vessel direction. The estimating, extracting, edge-enhancing, locating, finding, and extrapolating steps are repeated to track the vessel.
According to another aspect of the invention, a medical imaging method is disclosed. Computed tomography (CT) data is collected for a plurality of slices. At least a portion of the CT data is reconstructed to form a volume image defined by a plurality of two-dimensional image slices. At least one starting point is identified within a blood vessel imaged in the three-dimensional image volume. The blood vessel is recursively tracked to form a blood vessel representation.
According to yet another aspect of the invention, an apparatus for tracking one of a blood vessel and a tubular organ in a patient is disclosed. A computed tomography scanner acquires three-dimensional image data. A reconstruction processor reconstructs the three-dimensional image data into a three-dimensional image representation. A tracking processor tracks the blood vessel in the three-dimensional image representation.
According to still yet another aspect of the invention, an apparatus for tracking one of a blood vessel and a tubular organ in a patient is disclosed. A computed tomography scanner acquires three-dimensional image data. A reconstruction processor reconstructs the three-dimensional image data into a three-dimensional image representation. A means is provided for estimating a vessel direction at a user selected starting point. A means is provided for extracting an image plane orthogonal to the vessel direction and containing the starting point. A means is provided for determining at least one of a vessel center and vessel edges in the image plane. A means is provided for identifying a new point based on the estimated vessel direction. A means is provided for the estimating, extracting, determining, and identifying being repeated a plurality of times to effectuate the tracking.
One advantage of the present invention is that it provides a direct approach for extracting the vessel centerline in multi-slice CT data.
Another advantage of the present invention is that it automatically extracts the vessel boundaries to provide accurate lumen information in the tracked vasculature.
Another advantage of the present invention is that it detects vessel branches. This facilitates generation of the vascular tree structure by successive applications of the vessel tracking.
Yet another advantage of the present invention is that it assesses the optimal phase in retrospective cardiac gating.
Numerous additional advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments.